The present invention relates to apparatus for diverting or switching articles and particularly to apparatus for diverting articles from a first conveyor to at least one additional conveyor if the value of a sensed characteristic of the article differs by more than a predetermined amount from a preselected value.
In many manufacturing activities it is desirable to divert or switch selected articles travelling in a line on one conveyor to one or more additional conveyors leading, for example, to similar processing stations operating in parallel, according to available capacity.
In other manufacturing activities the finished product is required to have a certain characteristic, such as weight, maintained within predetermined limits. For example, in the food industry a line of containers typically is transported on a conveyor past a filling station to be filled with food items. After filling, the containers continue to be transported by the conveyor past a sensing station where the value of a characteristic, such as weight or fill level, is determined. If the value of the characteristic falls outside a predetermined range, the container is diverted to another conveyor line, either for return to the filling station or for other remedial action to bring the measured characteristic within the desired limits. In the simplest case, all out-of-limits articles may be returned for refilling. In other cases, it may be desirable to treat out-of-limits articles differently, depending upon whether the sensed value is over or under the desired value and the amount by which the sensed value differs from the desired value.
For example, in packing some food items a certain amount of moisture or liquid is permitted in the packaged product. If a container is initially filled with items containing less moisture than the permitted maximum, it may be possible to remedy slight underfilling by adding corresponding amounts of liquid to the container. In such a situation it is desirable to be able to divert containers to any one of several additional conveyor lines. For example, one conveyor line can pass a station adapted to add one ounce of liquid to containers that were no more than one ounce underweight, another line can pass a station adapted to add two ounces of liquid to containers between one and two ounces underweight, and so on, and a final line can return a container for dumping and refilling if it is overweight, or more than a correctable amount underweight.